New Hampshire has very specific requirements for the placement of Smoke and CO detectors. The law and administrative rules (RSA 153:10-a, among others) specifies the smoke alarm type, placement, and power requirements in the Granite State. You should update your home now to comply with these guidelines even if you are not selling now. When you go to sell, you may be asked to do this anyway, so updating your home now will save you time, will result in fewer inspection findings, and will make your home safer for your family.
Old smoke alarms may no longer be functional. All smoke alarms should be updated every 10 years. The same applies for CO detectors except that they should be replaced every 5 to 7 years.
Smoke and CO detectors need fresh batteries. Even hardwired models need batteries. Dead or missing batteries could result in death. It is a good practice to change your batteries when you change your clocks.
Click the links below for more information from the State of NH Fire Marshall in Concord.